Editing Permafrost (section)

== Impacts of climate change ==
{{See also|Effects of climate change}}
[[File:Beaufort Permafrost2.JPG|thumb|left|Recently thawed Arctic permafrost and coastal erosion on the Beaufort Sea, Arctic Ocean, near [[Point Lonely Short Range Radar Site|Point Lonely, Alaska]] in 2013.]]

=== Increasing active layer thickness ===
Globally, permafrost warmed by about {{cvt|0.3|C-change}} between 2007 and 2016, with stronger warming observed in the continuous permafrost zone relative to the discontinuous zone. Observed warming was up to {{convert|3|C-change|F-change}} in parts of [[Northern Alaska]] (early 1980s to mid-2000s) and up to {{convert|2|C-change|F-change}} in parts of the Russian European North (1970–2020). This warming inevitably causes permafrost to thaw: [[active layer]] thickness has increased in the European and [[Russian Arctic]] across the 21st century and at high elevation areas in Europe and Asia since the 1990s.<ref name="AR6_WG1_Chapter922">Fox-Kemper, B., H. T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S. S. Drijfhout, T. L. Edwards, N. R. Golledge, M. Hemer, R. E. Kopp, G.&nbsp; Krinner, A. Mix, D. Notz, S. Nowicki, I. S. Nurhati, L. Ruiz, J.-B. Sallée, A. B. A. Slangen, and Y. Yu, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter09.pdf Chapter 9: Ocean, Cryosphere and Sea Level Change]. In [https://www.ipcc.ch/report/ar6/wg1/ ''Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change''.] [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L.&nbsp; Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1211–1362, doi:10.1017/9781009157896.011.</ref>{{rp|1237}}

Between 2000 and 2018, the average active layer thickness had increased from ~{{convert|127|cm|ft}} to ~{{convert|145|cm|ft}}, at an average annual rate of ~{{convert|0.65|cm|in}}.<ref name="Li2022" />

In [[Yukon]], the zone of continuous permafrost might have moved {{convert|100|km}} poleward since 1899, but accurate records only go back 30 years. The extent of subsea permafrost is decreasing as well; as of 2019, ~97% of permafrost under Arctic ice shelves is becoming warmer and thinner.<ref>{{Cite journal |last1=Overduin |first1=P. P. |last2=Schneider von Deimling |first2=T. |last3=Miesner |first3=F. |last4=Grigoriev |first4=M. N. |last5=Ruppel |first5=C. |last6=Vasiliev |first6=A. |last7=Lantuit |first7=H. |last8=Juhls |first8=B. |last9=Westermann |first9=S. |date=17 April 2019 |title=Submarine Permafrost Map in the Arctic Modeled Using 1-D Transient Heat Flux (SuPerMAP) |journal=Journal of Geophysical Research: Oceans |volume=124 |issue=6 |pages=3490–3507 |doi=10.1029/2018JC014675 |bibcode=2019JGRC..124.3490O |hdl=1912/24566 |s2cid=146331663 |url=https://epic.awi.de/id/eprint/49740/1/Overduin_etal2019_ePIC.pdf }}</ref><ref name="AR6_WG1_Chapter92" />{{rp|1281}}

Based on high agreement across model projections, fundamental process understanding, and paleoclimate evidence, it is virtually certain that permafrost extent and volume will continue to shrink as the global climate warms, with the extent of the losses determined by the magnitude of warming.<ref name="AR6_WG1_Chapter922" />{{rp|1283}}

Permafrost thaw is associated with a wide range of issues, and [[International Permafrost Association]] (IPA) exists to help address them. It convenes International Permafrost Conferences and maintains [[Global Terrestrial Network for Permafrost]], which undertakes special projects such as preparing databases, maps, bibliographies, and glossaries, and coordinates international field programmes and networks.<ref>{{cite web|author= |url=https://www.permafrost.org/frozen-ground-newsletter/ |title=Frozen Ground, the News Bulletin of the IPA |language= |website=International Permafrost Association |date= 2014-02-10|accessdate=2016-04-28}}</ref>

=== Climate change feedback ===
{{Main|Permafrost carbon cycle}}
[[File:Hugelius 2020 peatland projections.jpg|thumb|Permafrost peatlands (a smaller, carbon-rich subset of permafrost areas) under varying extent of global warming, and the resultant emissions as a fraction of anthropogenic emissions needed to cause that extent of warming.<ref name="Hugelius2020">{{Cite journal |last1=Hugelius |first1=Gustaf |last2=Loisel |first2=Julie |last3=Chadburn |first3=Sarah |display-authors=etal |date=10 August 2020 |title=Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw |journal=Proceedings of the National Academy of Sciences |volume=117 |issue=34 |pages=20438–20446 |bibcode=2020PNAS..11720438H |doi=10.1073/pnas.1916387117 |pmc=7456150 |pmid=32778585 |doi-access=free}}</ref>
]]

As recent warming deepens the active layer subject to permafrost thaw, this exposes formerly stored [[carbon]] to biogenic processes which facilitate its entrance into the atmosphere as [[carbon dioxide]] and [[methane]].<ref name="Schuur2022" /> Because carbon emissions from permafrost thaw contribute to the same warming which facilitates the thaw, it is a well-known example of a [[Climate change feedback#Positive feedbacks|positive climate change feedback]].<ref name="Natali2020">{{Cite journal |last1=Natali |first1=Susan M. |last2=Holdren |first2=John P. |last3=Rogers |first3=Brendan M. |last4=Treharne |first4=Rachael |last5=Duffy |first5=Philip B. |last6=Pomerance |first6=Rafe |last7=MacDonald |first7=Erin |date=10 December 2020 |title=Permafrost carbon feedbacks threaten global climate goals |journal=Proceedings of the National Academy of Sciences |volume=118 |issue=21 |doi=10.1073/pnas.2100163118 |pmc=8166174 |pmid=34001617 |doi-access=free}}</ref> Permafrost thaw is sometimes included as one of the major [[tipping points in the climate system]] due to the exhibition of local thresholds and its effective irreversibility.<ref name="ArmstrongMcKay2022">{{Cite journal |last1=Armstrong McKay |first1=David |last2=Abrams |first2=Jesse |last3=Winkelmann |first3=Ricarda |last4=Sakschewski |first4=Boris |last5=Loriani |first5=Sina |last6=Fetzer |first6=Ingo |last7=Cornell |first7=Sarah |last8=Rockström |first8=Johan |last9=Staal |first9=Arie |last10=Lenton |first10=Timothy |date=9 September 2022 |title=Exceeding 1.5°C global warming could trigger multiple climate tipping points |url=https://www.science.org/doi/10.1126/science.abn7950 |journal=Science |language=en |volume=377 |issue=6611 |pages=eabn7950 |doi=10.1126/science.abn7950 |issn=0036-8075 |pmid=36074831 |s2cid=252161375 |hdl-access=free |hdl=10871/131584}}</ref> However, while there are self-perpetuating processes that apply on the local or regional scale, it is debated as to whether it meets the strict definition of a global tipping point as in aggregate permafrost thaw is gradual with warming.<ref>{{Cite journal |last1=Nitzbon |first1=J. |last2=Schneider von Deimling |first2=T. |last3=Aliyeva |first3=M. |date=2024 |title=No respite from permafrost-thaw impacts in the absence of a global tipping point. |url=https://doi.org/10.1038/s41558-024-02011-4 |journal=Nature Climate Change |volume=14 |issue=6 |pages=573–585|doi=10.1038/s41558-024-02011-4 |bibcode=2024NatCC..14..573N }}</ref>
[[File:Fig 1.2.15 Schematic showing feedback processes related to land and subsea permafrost..png|thumb|Feedback processes related to land and subsea permafrost.]]
In the northern circumpolar region, permafrost contains organic matter equivalent to 1400–1650&nbsp;billion tons of pure carbon, which  was built up over thousands of years. This amount equals almost half of all organic material in all [[soil]]s,<ref name="Tarnocai2009">{{cite journal |last1=Tarnocai, C. |author2=Canadell, J. G. |author3=Schuur, E. A. G. |author4=Kuhry, P. |author5=Mazhitova, G. |author6=Zimov, S. |date=June 2009 |title=Soil organic carbon pools in the northern circumpolar permafrost region |journal=Global Biogeochemical Cycles |volume=23 |issue=2 |page=GB2023 |bibcode=2009GBioC..23.2023T |doi=10.1029/2008gb003327 |doi-access=free}}</ref><ref name="Schuur2022" /> and it is about twice the carbon content of the [[atmosphere]], or around four times larger than the human emissions of carbon between the start of the [[Industrial Revolution]] and 2011.<ref name="Schuur2011">{{cite journal |last1=Schuur |display-authors=etal |year=2011 |title=High risk of permafrost thaw |url=https://digital.library.unt.edu/ark:/67531/metadc836756/ |journal=Nature |volume=480 |issue=7375 |pages=32–33 |bibcode=2011Natur.480...32S |doi=10.1038/480032a |pmid=22129707 |s2cid=4412175 |doi-access=free}}</ref> Further, most of this carbon (~1,035&nbsp;billion tons) is stored in what is defined as the near-surface permafrost, no deeper than {{convert|3|m|ft}} below the surface.<ref name="Tarnocai2009" /><ref name="Schuur2022" /> However, only a fraction of this stored carbon is expected to enter the atmosphere.<ref name="Bockheim2007">{{Cite journal |author1=Bockheim, J.G. |author2=Hinkel, K.M. |name-list-style=amp |year=2007 |title=The importance of "Deep" organic carbon in permafrost-affected soils of Arctic Alaska |url=http://soil.scijournals.org/cgi/content/abstract/71/6/1889 |url-status=dead |journal=Soil Science Society of America Journal |volume=71 |issue=6 |pages=1889–92 |bibcode=2007SSASJ..71.1889B |doi=10.2136/sssaj2007.0070N |archive-url=https://web.archive.org/web/20090717063627/http://soil.scijournals.org/cgi/content/abstract/71/6/1889 |archive-date=17 July 2009 |access-date=5 June 2010}}</ref> In general, the volume of permafrost in the upper 3&nbsp;m of ground is expected to decrease by about 25% per {{convert|1|C-change|F-change}} of global warming,<ref name="AR6_WG1_Chapter922" />{{rp|1283}} yet even under the [[Representative Concentration Pathway#RCP8.5|RCP8.5]] scenario associated with over {{convert|4|C-change|F-change}} of global warming by the end of the 21st century,<ref name="ar5 21st century projections">IPCC: Table SPM-2, in: [http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf Summary for Policymakers] (archived [https://web.archive.org/web/20140716042158/http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf 16 July 2014]), in: {{harvnb|IPCC AR5 WG1|2013|p=21}}</ref> about 5% to 15% of permafrost carbon is expected to be lost "over decades and centuries".<ref name="Schuur2022" />

The exact amount of carbon that will be released due to warming in a given permafrost area depends on depth of thaw, carbon content within the thawed soil, physical changes to the environment, and microbial and vegetation activity in the soil.<ref name="Nowinski2010">{{Cite journal |vauthors=Nowinski NS, Taneva L, [[Susan Trumbore|Trumbore SE]], Welker JM |date=January 2010 |title=Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment |journal=Oecologia |volume=163 |issue=3 |pages=785–92 |bibcode=2010Oecol.163..785N |doi=10.1007/s00442-009-1556-x |pmc=2886135 |pmid=20084398}}</ref> Notably, estimates of carbon release alone do not fully represent the impact of permafrost thaw on climate change. This is because carbon can be released through either [[aerobic respiration|aerobic]] or [[anaerobic respiration]], which results in carbon dioxide (CO<sub>2</sub>) or methane (CH<sub>4</sub>) emissions, respectively. While methane lasts less than 12 years in the atmosphere, its [[global warming potential]] is around 80 times larger than that of CO<sub>2</sub> over a 20-year period and about 28 times larger over a 100-year period.<ref>{{Cite book |last1=Forster |first1=Piers |title={{Harvnb|IPCC AR6 WG1|2021}} |last2=Storelvmo |first2=Trude |year=2021 |chapter=Chapter 7: The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity |ref={{harvid|IPCC AR6 WG1 Ch7|2021}} |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf}}</ref><ref>{{Cite journal |last1=Allen |first1=Robert J. |last2=Zhao |first2=Xueying |last3=Randles |first3=Cynthia A. |last4=Kramer |first4=Ryan J. |last5=Samset |first5=Bjørn H. |last6=Smith |first6=Christopher J. |date=16 March 2023 |title=Surface warming and wetting due to methane's long-wave radiative effects muted by short-wave absorption |journal=Nature Geoscience |volume=16 |issue=4 |pages=314–320 |bibcode=2023NatGe..16..314A |doi=10.1038/s41561-023-01144-z |s2cid=257595431}}</ref> While only a small fraction of permafrost carbon will enter the atmosphere as methane, those emissions will cause 40–70% of the total warming caused by permafrost thaw during the 21st century. Much of the uncertainty about the eventual extent of permafrost methane emissions is caused by the difficulty of accounting for the recently discovered abrupt thaw processes, which often increase the fraction of methane emitted over carbon dioxide in comparison to the usual gradual thaw processes.<ref>{{Cite journal |last1=Miner |first1=Kimberley R. |last2=Turetsky |first2=Merritt R. |last3=Malina |first3=Edward |last4=Bartsch |first4=Annett |last5=Tamminen |first5=Johanna |last6=McGuire |first6=A. David |last7=Fix |first7=Andreas |last8=Sweeney |first8=Colm |last9=Elder |first9=Clayton D. |last10=Miller |first10=Charles E. |date=11 January 2022 |title=Permafrost carbon emissions in a changing Arctic |url=https://www.nature.com/articles/s43017-021-00230-3 |journal=Nature Reviews Earth & Environment |volume=13 |issue=1 |pages=55–67 |bibcode=2022NRvEE...3...55M |doi=10.1038/s43017-021-00230-3 |s2cid=245917526}}</ref><ref name="Schuur2022" />
[[File:Permafrost thaw ponds in Hudson Bay Canada near Greenland.jpg|thumb|left|Permafrost thaw ponds on peatland in [[Hudson Bay]], Canada in 2008.<ref>{{cite journal |last1=Dyke |first1=Larry D. |last2=Sladen |first2=Wendy E. |date=3 December 2010 |title=Permafrost and Peatland Evolution in the Northern Hudson Bay Lowland, Manitoba |journal=Arctic |volume=63 |issue=4 |pages=429–441 |doi=10.14430/arctic3332 |doi-access=free}}</ref>]]
Another factor which complicates projections of permafrost carbon emissions is the ongoing "greening" of the Arctic. As climate change warms the air and the soil, the region becomes more hospitable to plants, including larger [[shrub]]s and trees which could not survive there before. Thus, the Arctic is losing more and more of its [[tundra]] biomes, yet it gains more plants, which proceed to absorb more carbon. Some of the emissions caused by permafrost thaw will be offset by this increased plant growth, but the exact proportion is uncertain. It is considered very unlikely that this greening could offset all of the emissions from permafrost thaw during the 21st century, and even less likely that it could continue to keep pace with those emissions after the 21st century.<ref name="Schuur2022" /> Further, climate change also increases the risk of [[wildfire]]s in the Arctic, which can substantially accelerate emissions of permafrost carbon.<ref name="Natali2020" /><ref>{{Cite journal |last1=Estop-Aragonés |first1=Cristian |last2=Czimczik |first2=Claudia I |last3=Heffernan |first3=Liam |last4=Gibson |first4=Carolyn |last5=Walker |first5=Jennifer C |last6=Xu |first6=Xiaomei |last7=Olefeldt |first7=David |date=13 August 2018 |title=Respiration of aged soil carbon during fall in permafrost peatlands enhanced by active layer deepening following wildfire but limited following thermokarst |journal=Environmental Research Letters |volume=13 |issue=8 |doi=10.1088/1748-9326/aad5f0|bibcode=2018ERL....13h5002E |s2cid=158857491 |doi-access=free }}</ref>

==== Impact on global temperatures ====
[[File:Schuur 2022 century-scale permafrost projections.jpeg|thumb|Nine probable scenarios of [[greenhouse gas emission]]s from permafrost thaw during the 21st century, which show a limited, moderate and intense {{CO2}} and {{CH4}} emission response to low, medium and high-emission [[Representative Concentration Pathway]]s. The vertical bar uses emissions of selected large countries as a comparison: the right-hand side of the scale shows their cumulative emissions since the start of the [[Industrial Revolution]], while the left-hand side shows each country's cumulative emissions for the rest of the 21st century if they remained unchanged from their 2019 levels.<ref name="Schuur2022" />]]

Altogether, it is expected that cumulative greenhouse gas emissions from permafrost thaw will be smaller than the cumulative anthropogenic emissions, yet still substantial on a global scale, with some experts comparing them to emissions caused by [[deforestation]].<ref name="Schuur2022" /> The [[IPCC Sixth Assessment Report]] estimates that carbon dioxide and methane released from permafrost could amount to the equivalent of 14–175&nbsp;billion tonnes of carbon dioxide per {{convert|1|C-change|F-change}} of warming.<ref name="AR6_WG1_Chapter922" />{{rp|1237}}  For comparison, by 2019, annual anthropogenic emissions of carbon dioxide alone stood around 40&nbsp;billion tonnes.<ref name="AR6_WG1_Chapter922" />{{rp|1237}} A major review published in the year 2022 concluded that if the goal of preventing {{convert|2|C-change|F-change}} of warming was realized, then the average annual permafrost emissions throughout the 21st century would be equivalent to the year 2019 annual emissions of Russia. Under RCP4.5, a scenario considered close to the current trajectory and where the warming stays slightly below {{convert|3|C-change|F-change}}, annual permafrost emissions would be comparable to year 2019 emissions of Western Europe or the United States, while under the scenario of high global warming and worst-case permafrost feedback response, they would approach year 2019 emissions of China.<ref name="Schuur2022" />

Fewer studies have attempted to describe the impact directly in terms of warming. A 2018 paper estimated that if global warming was limited to {{convert|2|C-change|F-change}}, gradual permafrost thaw would add around {{convert|0.09|C-change|F-change}} to global temperatures by 2100,<ref>{{Cite journal |last1=Schellnhuber |first1=Hans Joachim |last2=Winkelmann |first2=Ricarda |last3=Scheffer |first3=Marten |last4=Lade |first4=Steven J. |last5=Fetzer |first5=Ingo |last6=Donges |first6=Jonathan F. |last7=Crucifix |first7=Michel |last8=Cornell |first8=Sarah E. |last9=Barnosky |first9=Anthony D. |author-link9=Anthony David Barnosky |date=2018 |title=Trajectories of the Earth System in the Anthropocene |journal=[[Proceedings of the National Academy of Sciences]] |volume=115 |issue=33 |pages=8252–8259 |bibcode=2018PNAS..115.8252S |doi=10.1073/pnas.1810141115 |issn=0027-8424 |pmc=6099852 |pmid=30082409 |doi-access=free}}</ref> while a 2022 review concluded that every {{convert|1|C-change|F-change}} of global warming would cause {{convert|0.04|C-change|F-change}} and {{convert|0.11|C-change|F-change}} from abrupt thaw by the year 2100 and 2300. Around {{convert|4|C-change|F-change}} of global warming, abrupt (around 50 years) and widespread collapse of permafrost areas could occur, resulting in an additional warming of {{convert|0.2-0.4|C-change|F-change}}.<ref name="ArmstrongMcKay2022" /><ref>{{Cite web |last=Armstrong McKay |first=David |date=9 September 2022 |title=Exceeding 1.5°C global warming could trigger multiple climate tipping points – paper explainer |url=https://climatetippingpoints.info/2022/09/09/climate-tipping-points-reassessment-explainer/ |access-date=2 October 2022 |website=climatetippingpoints.info |language=en}}</ref>

=== Thaw-induced ground instability ===
[[File:Permafrost coastal erosion USGS.png|thumb|Severe [[coastal erosion]] on the Arctic Ocean coast of [[Alaska]].]]
[[File:Permafrost revealed by coastal erosion (9354).jpg|thumb|Permafrost revealed by coastal erosion in Alaska.]]
As the water drains or evaporates, soil structure weakens and sometimes becomes viscous until it regains strength with decreasing moisture content. One visible sign of permafrost degradation is the [[Drunken trees|random displacement of trees from their vertical orientation]] in permafrost areas.<ref>{{Cite book|last=Huissteden|first=J. van|url=https://books.google.com/books?id=mZPHDwAAQBAJ&q=permafrost+thaw|title=Thawing Permafrost: Permafrost Carbon in a Warming Arctic|date=2020|publisher=Springer Nature|isbn=978-3-030-31379-1|page=296 }}</ref> Global warming has been increasing permafrost slope disturbances and sediment supplies to fluvial systems, resulting in exceptional increases in river sediment.<ref>{{cite journal |last1=Li |first1=Dongfeng |last2=Lu |first2=Xixi |last3=Overeem |first3=Irina |last4=Walling |first4=Desmond E. |last5=Syvitski |first5=Jaia |last6=Kettner |first6=Albert J. |last7=Bookhagen |first7=Bodo |last8=Zhou |first8=Yinjun |last9=Zhang |first9=Ting |title=Exceptional increases in fluvial sediment fluxes in a warmer and wetter High Mountain Asia |journal=Science |date=29 October 2021 |volume=374 |issue=6567 |pages=599–603 |doi=10.1126/science.abi9649 |pmid=34709922 |bibcode=2021Sci...374..599L |s2cid=240152765 }}</ref> On the other hands, disturbance of formerly hard soil increases drainage of water reservoirs in northern [[wetland]]s. This can dry them out and compromise the survival of plants and animals used to the wetland ecosystem.<ref>{{Cite journal|last1=Koven|first1=Charles D.|last2=Riley|first2=William J.|last3=Stern|first3=Alex|date=2012-10-01|title=Analysis of Permafrost Thermal Dynamics and Response to Climate Change in the CMIP5 Earth System Models|journal=Journal of Climate|volume=26|issue=6|pages=1877–1900|doi=10.1175/JCLI-D-12-00228.1|osti=1172703 |url=http://www.escholarship.org/uc/item/9cv093s8|doi-access=free}}</ref>

In high mountains, much of the structural stability can be attributed to [[glacier]]s and permafrost.<ref>{{Cite journal |last1=Huggel |first1=C. |last2=Allen |first2=S. |last3=Deline |first3=P. |title=Ice thawing, mountains falling; are alpine rock slope failures increasing? |journal=Geology Today |volume=28 |issue=3 |pages=98–104 |date=June 2012 |doi=10.1111/j.1365-2451.2012.00836.x |bibcode=2012GeolT..28...98H |s2cid=128619284 }}</ref> As climate warms, permafrost thaws, decreasing slope stability and increasing stress through buildup of [[pore-water]] pressure, which may ultimately lead to slope failure and [[rockfall]]s.<ref>{{cite book|last1=Nater|first1=P.|last2=Arenson|first2=L.U.|last3=Springman|first3=S.M.|title=Choosing geotechnical parameters for slope stability assessments in alpine permafrost soils. In 9th international conference on permafrost.|date=2008|publisher=University of Alaska|location=Fairbanks, USA|isbn=978-0-9800179-3-9|pages=1261–1266}}</ref><ref name=Arnaud>{{Cite journal|last=Temme|first=Arnaud J. A. M.|date=2015|title=Using Climber's Guidebooks to Assess Rock Fall Patterns Over Large Spatial and Decadal Temporal Scales: An Example from the Swiss Alps|journal=Geografiska Annaler: Series A, Physical Geography |volume=97|issue=4|pages=793–807|doi=10.1111/geoa.12116|bibcode=2015GeAnA..97..793T |s2cid=55361904}}</ref> Over the past century, an increasing number of alpine rock slope failure events in mountain ranges around the world have been recorded, and some have been attributed to permafrost thaw induced by climate change. The 1987 [[Val Pola landslide]] that killed 22 people in the [[Italian Alps]] is considered one such example.<ref>{{Cite journal|last1=F.|first1=Dramis|last2=M.|first2=Govi|last3=M.|first3=Guglielmin|last4=G.|first4=Mortara|date=1995-01-01|title=Mountain permafrost and slope instability in the Italian Alps: The Val Pola Landslide|journal=Permafrost and Periglacial Processes|volume=6|issue=1|doi=10.1002/ppp.3430060108 |pages=73–81|bibcode=1995PPPr....6...73D }}</ref> In 2002, massive rock and ice falls (up to 11.8&nbsp;million m<sup>3</sup>), earthquakes (up to 3.9 [[Richter scale|Richter]]), floods (up to 7.8&nbsp;million m<sup>3</sup> water), and rapid rock-ice flow to long distances (up to 7.5&nbsp;km at 60&nbsp;m/s) were attributed to slope instability in high mountain permafrost.<ref>{{cite book |doi=10.1130/REG15 |title=Catastrophic Landslides: Effects, Occurrence, and Mechanisms |series=Reviews in Engineering Geology |year=2002 |volume=15 |isbn=0-8137-4115-7 }}</ref>
[[File:Permafrost in Herschel Island 001.jpg|thumb|left|Thawing permafrost in [[Herschel Island]], Canada, 2013.]]
Permafrost thaw can also result in the formation of frozen debris lobes (FDLs), which are defined as "slow-moving landslides composed of soil, rocks, trees, and ice".<ref name="UAF FDLs 2022">{{Cite web| title = FDL: Frozen Debris Lobes | date = 7 January 2022| access-date = 7 January 2022 |series=FDLs |work=[[University of Alaska Fairbanks]]| url = https://fdlalaska.org/}}</ref> This is a notable issue in the [[Alaska]]'s southern [[Brooks Range]], where some FDLs measured over {{convert|100|metre|yards|abbr=on}} in width, {{convert|20|metre|yards|abbr=on}} in height, and {{convert|1000|metre|yards|abbr=on}} in length by 2012.<ref name="Daanen 2012">{{Cite journal | doi = 10.5194/nhess-12-1521-2012 | volume = 12 | pages = 1521–1537 | last1 = Daanen | first1 = Ronald | last2 = Grosse | first2 = Guido | last3 = Darrow | first3 = Margaret | last4 = Hamilton | first4 = T. | last5 = Jones
| first5 = Benjamin | title = Rapid movement of frozen debris-lobes: Implications for permafrost degradation and slope instability in the south-central Brooks Range, Alaska | journal = Natural Hazards and Earth System Sciences
| date = 21 May 2012| issue = 5 | bibcode = 2012NHESS..12.1521D | doi-access = free }}</ref><ref name="Darrow 2016">{{cite journal |last1=Darrow |first1=Margaret M. |last2=Gyswyt |first2=Nora L. |last3=Simpson |first3=Jocelyn M. |last4=Daanen |first4=Ronald P. |last5=Hubbard |first5=Trent D. |title=Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |journal=The Cryosphere |date=12 May 2016 |volume=10 |issue=3 |pages=977–993 |doi=10.5194/tc-10-977-2016 |bibcode=2016TCry...10..977D |doi-access=free }}</ref> As of December 2021, there were 43 frozen debris lobes identified in the southern Brooks Range, where they could potentially threaten both the [[Trans Alaska Pipeline System]] (TAPS) corridor and the [[Dalton Highway]], which is the main transport link between the [[Interior Alaska]] and the [[Alaska North Slope]].<ref name="Hasemyer 2021">{{Cite web | last = Hasemyer| first = David| title = Unleashed by Warming, Underground Debris Fields Threaten to 'Crush' Alaska's Dalton Highway and the Alaska Pipeline | work = Inside Climate News | access-date = 7 January 2022| date = 20 December 2021| url = https://insideclimatenews.org/news/20122021/alaska-frozen-debris-lobes-dalton-highway-pipeline-climate-change/}}</ref>

==== Infrastructure ====
[[File:Hjort 2018 permafrost infrastructure.png|thumb|Map of likely risk to infrastructure from permafrost thaw expected to occur by 2050.<ref name="Hjort2018" />]]
As of 2021, there are 1162 settlements located directly atop the Arctic permafrost, which host an estimated 5 million people. By 2050, permafrost layer below 42% of these settlements is expected to thaw, affecting all their inhabitants (currently 3.3&nbsp;million people).<ref>{{Cite journal |last1=Ramage |first1=Justine |last2=Jungsberg |first2=Leneisja |last3=Wang |first3=Shinan |last4=Westermann |first4=Sebastian |last5=Lantuit |first5=Hugues |last6=Heleniak |first6=Timothy |date=6 January 2021 |title=Population living on permafrost in the Arctic |journal=Population and Environment |volume=43 |issue=1 |pages=22–38 |doi=10.1007/s11111-020-00370-6|bibcode=2021PopEn..43...22R |s2cid=254938760 }}</ref> Consequently, a wide range of infrastructure in permafrost areas is threatened by the thaw.<ref name="Nelson2002">{{Cite journal|last1=Nelson|first1=F. E.|last2=Anisimov|first2=O. A.|last3=Shiklomanov|first3=N. I.|date=2002-07-01|title=Climate Change and Hazard Zonation in the Circum-Arctic Permafrost Regions|journal=Natural Hazards |volume=26|issue=3|pages=203–225|doi=10.1023/A:1015612918401|bibcode=2002NatHa..26..203N |s2cid=35672358 }}</ref><ref>{{Cite book |last1=Barry |first1=Roger Graham |title=The global cryosphere past, present and future |last2=Gan |first2=Thian-Yew |date=2021 |isbn=978-1-108-48755-9 |edition=Second revised |location=Cambridge, United Kingdom |oclc=1256406954 |publisher=Cambridge University Press}}</ref>{{rp|236}} By 2050, it's estimated that nearly 70% of global infrastructure located in the permafrost areas would be at high risk of permafrost thaw, including 30–50% of "critical" infrastructure. The associated costs could reach tens of billions of dollars by the second half of the century.<ref name="Hjort2022">{{Cite journal |last1=Hjort |first1=Jan |last2=Streletskiy |first2=Dmitry |last3=Doré |first3=Guy |last4=Wu |first4=Qingbai |last5=Bjella |first5=Kevin |last6=Luoto |first6=Miska |date=11 January 2022 |title=Impacts of permafrost degradation on infrastructure |journal=Nature Reviews Earth & Environment |volume=3 |issue=1 |pages=24–38 |doi=10.1038/s43017-021-00247-8|bibcode=2022NRvEE...3...24H |hdl=10138/344541 |s2cid=245917456 |url=http://urn.fi/urn:nbn:fi-fe2022101962575 |hdl-access=free }}</ref> Reducing [[greenhouse gas emissions]] in line with the [[Paris Agreement]] is projected to stabilize the risk after mid-century; otherwise, it'll continue to worsen.<ref name="Hjort2018" />

In [[Alaska]] alone, damages to infrastructure by the end of the century would amount to $4.6&nbsp;billion (at 2015 dollar value) if [[Representative Concentration Pathway|RCP8.5]], the high-emission [[climate change scenario]], were realized. Over half stems from the damage to buildings ($2.8&nbsp;billion), but there's also damage to roads ($700&nbsp;million), railroads ($620&nbsp;million), airports ($360&nbsp;million) and [[pipeline transport|pipelines]] ($170&nbsp;million).<ref name="Melvin2016">{{Cite journal |last1=Melvin|first1=April M.|last2=Larsen|first2=Peter|last3=Boehlert|first3=Brent |last4=Neumann|first4=James E.|last5=Chinowsky|first5=Paul|last6=Espinet|first6=Xavier|last7=Martinich|first7=Jeremy|last8=Baumann |first8=Matthew S.|last9=Rennels|first9=Lisa|last10=Bothner|first10=Alexandra|last11=Nicolsky|first11=Dmitry J.|last12=Marchenko |first12=Sergey S. |date=26 December 2016 |title=Climate change damages to Alaska public infrastructure and the economics of proactive adaptation |journal=Proceedings of the National Academy of Sciences |volume=114 |issue=2 |pages=E122–E131 |doi=10.1073/pnas.1611056113 |pmid=28028223 |pmc=5240706 |doi-access=free }}</ref> Similar estimates were done for RCP4.5, a less intense scenario which leads to around {{convert|2.5|C-change|F-change}} by 2100, a level of warming similar to the current projections.<ref name="CAT">{{cite web |url=https://climateactiontracker.org/global/cat-thermometer/ |title=The CAT Thermometer |access-date=25 April 2023}}</ref> In that case, total damages from permafrost thaw are reduced to $3&nbsp;billion, while damages to roads and railroads are lessened by approximately two-thirds (from $700 and $620&nbsp;million to $190 and $220&nbsp;million) and damages to pipelines are reduced more than ten-fold, from $170&nbsp;million to $16&nbsp;million. Unlike the other costs stemming from climate change in Alaska, such as damages from increased [[precipitation]] and flooding, [[climate change adaptation]] is not a viable way to reduce damages from permafrost thaw, as it would cost more than the damage incurred under either scenario.<ref name="Melvin2016" />

In Canada, [[Northwest Territories]] have a population of only 45,000 people in 33 communities, yet permafrost thaw is expected to cost them $1.3&nbsp;billion over 75 years, or around $51&nbsp;million a year. In 2006, the cost of adapting [[Inuvialuit]] homes to permafrost thaw was estimated at $208/m<sup>2</sup> if they were built at pile foundations, and $1,000/m<sup>2</sup> if they didn't. At the time, the average area of a residential building in the territory was around 100&nbsp;m<sup>2</sup>. Thaw-induced damage is also unlikely to be covered by [[home insurance]], and to address this reality, territorial government currently funds Contributing Assistance for Repairs and Enhancements (CARE) and Securing Assistance for Emergencies (SAFE) programs, which provide long- and short-term forgivable loans to help homeowners adapt. It is possible that in the future, mandatory relocation would instead take place as the cheaper option. However, it would effectively tear the local [[Inuit]] away from their ancestral homelands. Right now, their average personal income is only half that of the median NWT resident, meaning that adaptation costs are already disproportionate for them.<ref>{{Cite web|url=https://www.thearcticinstitute.org/reducing-individual-costs-permafrost-thaw-damage-canada-arctic/ |last=Tsui|first=Emily |title=Reducing Individual Costs of Permafrost Thaw Damage in Canada's Arctic |date=March 4, 2021|website=The Arctic Institute}}</ref>

By 2022, up to 80% of buildings in some Northern Russia cities had already experienced damage.<ref name="Hjort2022" /> By 2050, the damage to residential infrastructure may reach $15&nbsp;billion, while total public infrastructure damages could amount to 132&nbsp;billion.<ref>{{cite journal |last1=Melnikov |first1=Vladimir |last2=Osipov |first2=Victor |last3=Brouchkov |first3=Anatoly V. |last4=Falaleeva |first4=Arina A. |last5=Badina |first5=Svetlana V. |last6=Zheleznyak |first6=Mikhail N. |last7=Sadurtdinov |first7=Marat R. |last8=Ostrakov |first8=Nikolay A. |last9=Drozdov |first9=Dmitry S. |last10=Osokin |first10=Alexei B. |last11=Sergeev |first11=Dmitry O. |last12=Dubrovin |first12=Vladimir A. |last13=Fedorov  |first13=Roman Yu. |date=24 January 2022 |title=Climate warming and permafrost thaw in the Russian Arctic: potential economic impacts on public infrastructure by 2050 |journal=Natural Hazards |volume=112 |issue=1 |pages=231–251 |doi=10.1007/s11069-021-05179-6|bibcode=2022NatHa.112..231M |s2cid=246211747 }}</ref> This includes [[oil and gas]] extraction facilities, of which 45% are believed to be at risk.<ref name="Hjort2018">{{Cite journal |last1=Hjort |first1=Jan |last2=Karjalainen |first2=Olli |last3=Aalto |first3=Juha |last4=Westermann |first4=Sebastian |last5=Romanovsky |first5=Vladimir E. |last6=Nelson |first6=Frederick E. |last7=Etzelmüller |first7=Bernd |last8=Luoto |first8=Miska |date=11 December 2018 |title=Degrading permafrost puts Arctic infrastructure at risk by mid-century |journal=Nature Communications |volume=9 |issue=1 |page=5147 |doi=10.1038/s41467-018-07557-4 |pmid=30538247 |pmc=6289964 |bibcode=2018NatCo...9.5147H }}</ref>
[[File:Ran 2022 QTP Permafrost damages 2050.png|thumb|left|Detailed map of Qinghai–Tibet Plateau infrastructure at risk from permafrost thaw under the SSP2-4.5 scenario.<ref name="Ran2022" />]]
Outside of the Arctic, [[Qinghai–Tibet Plateau]] (sometimes known as "the Third Pole"), also has an extensive permafrost area. It is warming at twice the global average rate, and 40% of it is already considered "warm" permafrost, making it particularly unstable. Qinghai–Tibet Plateau has a population of over 10 million people – double the population of permafrost regions in the Arctic – and over 1&nbsp;million m<sup>2</sup> of buildings are located in its permafrost area, as well as 2,631&nbsp;km of [[power line]]s, and 580&nbsp;km of railways.<ref name="Ran2022" /> There are also 9,389&nbsp;km of roads, and around 30% are already sustaining damage from permafrost thaw.<ref name="Hjort2022" /> Estimates suggest that under the scenario most similar to today, [[Shared Socioeconomic Pathways|SSP2-4.5]], around 60% of the current infrastructure would be at high risk by 2090 and simply maintaining it would cost $6.31&nbsp;billion, with adaptation reducing these costs by 20.9% at most. Holding the global warming to {{convert|2|C-change|F-change}} would reduce these costs to $5.65&nbsp;billion, and fulfilling the optimistic [[Paris Agreement]] target of {{convert|1.5|C-change|F-change}} would save a further $1.32&nbsp;billion. In particular, fewer than 20% of railways would be at high risk by 2100 under {{convert|1.5|C-change|F-change}}, yet this increases to 60% at {{convert|2|C-change|F-change}}, while under SSP5-8.5, this level of risk is met by mid-century.<ref name="Ran2022">{{Cite journal |last1=Ran |first1=Youhua |last2=Cheng |first2=Guodong |last3=Dong |first3=Yuanhong |last4=Hjort |first4=Jan |last5=Lovecraft |first5=Amy Lauren |last6=Kang |first6=Shichang |last7=Tan |first7=Meibao |last8=Li |first8=Xin |date=13 October 2022 |title=Permafrost degradation increases risk and large future costs of infrastructure on the Third Pole |journal=Communications Earth & Environment |volume=3 |issue=1 |page=238 |doi=10.1038/s43247-022-00568-6 |bibcode=2022ComEE...3..238R |s2cid=252849121 }}</ref>

=== Release of toxic pollutants ===
[[File:Langer 2023 thawed pollution.png|thumb|Graphical representation of leaks from various toxic hazards caused by the thaw of formerly stable permafrost.<ref name="Langer2023" />]]
For much of the 20th century, it was believed that permafrost would "indefinitely" preserve anything buried there, and this made deep permafrost areas popular locations for hazardous waste disposal. In places like Canada's [[Prudhoe Bay]] oil field, procedures were developed documenting the "appropriate" way to inject waste beneath the permafrost. This means that as of 2023, there are ~4500 industrial facilities in the Arctic permafrost areas which either actively process or store hazardous chemicals. Additionally, there are between 13,000 and 20,000 sites which have been heavily contaminated, 70% of them in Russia, and their pollution is currently trapped in the permafrost.{{citation needed|date=August 2024}}

About a fifth of both the industrial and the polluted sites (1000 and 2200–4800) are expected to start thawing in the future even if the warming does not increase from its 2020 levels. Only about 3% more sites would start thawing between now and 2050 under the climate change scenario consistent with the [[Paris Agreement]] goals, [[Representative Concentration Pathway|RCP2.6]], but by 2100, about 1100 more industrial facilities and 3500 to 5200 contaminated sites are expected to start thawing even then. Under the very high emission scenario RCP8.5, 46% of industrial and contaminated sites would start thawing by 2050, and virtually all of them would be affected by the thaw by 2100.<ref name="Langer2023">{{Cite journal |last1=Langer |first1=Morit |last2=Schneider von Deimling |first2=Thomas |last3=Westermann |first3=Sebastian |last4=Rolph |first4=Rebecca |last5=Rutte |first5=Ralph |last6=Antonova |first6=Sofia |last7=Rachold |first7=Volker |last8=Schultz |first8=Michael |last9=Oehme |first9=Alexander |last10=Grosse |first10=Guido |date=28 March 2023 |title=Thawing permafrost poses environmental threat to thousands of sites with legacy industrial contamination |journal=Nature Communications |volume=14 |issue=1 |page=1721 |doi=10.1038/s41467-023-37276-4 |pmid=36977724 |pmc=10050325 |bibcode=2023NatCo..14.1721L }}</ref>

[[Organochlorine]]s and other [[persistent organic pollutant]]s are of a particular concern, due to their potential to repeatedly reach local communities after their re-release through [[biomagnification]] in fish. At worst, future generations born in the Arctic would enter life with weakened [[immune system]]s due to pollutants accumulating across generations.<ref name="Miner2021">{{Cite journal |last1=Miner |first1=Kimberley R. |last2=D'Andrilli |first2=Juliana |last3=Mackelprang |first3=Rachel |last4=Edwards |first4=Arwyn |last5=Malaska |first5=Michael J. |last6=Waldrop |first6=Mark P. |last7=Miller |first7=Charles E. |date=30 September 2021 |title=Emergent biogeochemical risks from Arctic permafrost degradation |journal=Nature Climate Change |volume=11 |issue=1 |pages=809–819 |doi=10.1038/s41558-021-01162-y |bibcode=2021NatCC..11..809M |s2cid=238234156 }}</ref>
[[File:Langer 2023 alaska distributions.png|thumb|left|Distribution of toxic substances currently located at various permafrost sites in Alaska, by sector. The number of fish skeletons represents the toxicity of each substance.<ref name="Langer2023" />]]
A notable example of pollution risks associated with permafrost was the [[2020 Norilsk oil spill]], caused by the collapse of [[diesel fuel]] storage tank at Norilsk-Taimyr Energy's [[thermal power plant]] No. 3. It spilled 6,000 tonnes of fuel into the land and 15,000 into the water, polluting [[Ambarnaya]], [[Daldykan]] and many smaller rivers on [[Taimyr Peninsula]], even reaching lake [[Pyasino]], which is a crucial water source in the area. [[State of emergency]] at the federal level was declared.<ref name=TASS>{{cite news |title=Diesel fuel spill in Norilsk in Russia's Arctic contained |url=https://tass.com/emergencies/1164423 |access-date=7 June 2020 |work=[[TASS]] |date=5 June 2020 |location=Moscow, Russia}}</ref><ref name="Seddon2020">{{Cite news |url=https://www.ft.com/content/fa9c20a0-2dad-4992-9686-0ec98b44faa8 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/fa9c20a0-2dad-4992-9686-0ec98b44faa8 |archive-date=10 December 2022 |url-access=subscription |title=Siberia fuel spill threatens Moscow's Arctic ambitions |author=Max Seddon |work=[[Financial Times]] |date=4 June 2020}}</ref> The event has been described as the second-largest oil spill in modern Russian history.<ref name=nyt>{{citation |url=https://www.nytimes.com/2020/06/04/world/europe/russia-oil-spill-arctic.html |title=Russia Declares Emergency After Arctic Oil Spill |last=Nechepurenko |first=Ivan |work=[[New York Times]] |date=5 June 2020}}</ref><ref>{{cite news |last1=Antonova |first1=Maria |title=Russia Says Melting Permafrost Is Behind The Massive Arctic Fuel Spill |url=https://www.sciencealert.com/russia-claims-melting-permafrost-is-behind-the-massive-arctic-fuel-spill |access-date=19 July 2020 |agency=Science Daily |date=5 June 2020}}</ref>

Another issue associated with permafrost thaw is the release of natural [[mercury (element)|mercury]] deposits. An estimated 800,000 tons of mercury are frozen in the permafrost soil. According to observations, around 70% of it is simply taken up by vegetation after the thaw.<ref name="Miner2021" /> However, if the warming continues under RCP8.5, then permafrost emissions of mercury into the [[atmosphere]] would match the current global emissions from all human activities by 2200. Mercury-rich soils also pose a much greater threat to humans and the environment if they thaw near rivers. Under RCP8.5, enough mercury will enter the [[Yukon River]] basin by 2050 to make its fish unsafe to eat under the [[EPA]] guidelines. By 2100, mercury concentrations in the river will double. Contrastingly, even if mitigation is limited to RCP4.5 scenario, mercury levels will increase by about 14% by 2100, and will not breach the EPA guidelines even by 2300.<ref name="Schaefer2020">{{Cite journal |last1=Schaefer |first1=Kevin |last2=Elshorbany |first2=Yasin |last3=Jafarov |first3=Elchin |last4=Schuster |first4=Paul F. |last5=Striegl |first5=Robert G. |last6=Wickland |first6=Kimberly P. |last7=Sunderland  |first7=Elsie M. |date=16 September 2020 |title=Potential impacts of mercury released from thawing permafrost |journal=Nature Communications |volume=11 |issue=1 |page=4650 |doi=10.1038/s41467-020-18398-5 |pmid=32938932 |pmc=7494925 |bibcode=2020NatCo..11.4650S }}</ref>

=== Revival of ancient organisms ===
==== Microorganisms ====
{{Main|Pathogenic microorganisms in frozen environments}}
[[File:Alempic 2023 permafrost viruses.jpg|thumb|left|Some of the ancient amoeba-eating viruses revived by the research team of Jean-Michel Claverie. Clockwise from the top: ''Pandoravirus yedoma''; ''Pandoravirus mammoth'' and ''Megavirus mammoth''; ''Cedratvirus lena''; ''Pithovirus mammoth''; ''Megavirus mammoth''; ''Pacmanvirus lupus''.<ref name="Alempic2023" />]]

Bacteria are known for being able to [[Dormancy#Bacteria|remain dormant]] to survive adverse conditions, and [[viruses]] are not metabolically active outside of host cells in the first place. This has motivated concerns that permafrost thaw could free previously unknown microorganisms, which may be capable of infecting either humans or important livestock and [[crops]], potentially resulting in damaging epidemics or [[pandemic]]s.<ref name="Alempic2023">{{Cite journal|last1=Alempic|first1=Jean-Marie|last2=Lartigue|first2=Audrey |last3=Goncharov|first3=Artemiy|last4=Grosse|first4=Guido|last5=Strauss |first5=Jens|last6=Tikhonov|first6=Alexey N. |last7=Fedorov|first7=Alexander N.|last8=Poirot|first8=Olivier|last9=Legendre|first9=Matthieu |last10=Santini|first10=Sébastien |last11=Abergel|first11=Chantal |last12=Claverie |first12=Jean-Michel |date=18 February 2023|title=An Update on Eukaryotic Viruses Revived from Ancient Permafrost |journal=Viruses|volume=15|issue=2|page=564 |doi=10.3390/v15020564 |pmid=36851778 |pmc=9958942 |doi-access=free}}</ref><ref name="Alund2023">{{Cite news|url=https://www.usatoday.com/story/news/health/2023/03/09/zombie-virus-frozen-permafrost-revived-after-50-000-years/11434218002/|title=Scientists revive 'zombie virus' that was frozen for nearly 50,000 years |first1=Natalie Neysa |last1=Alund |date=9 March 2023 |website=[[USA Today]] |access-date=2023-04-23}}</ref> Further, some scientists argue that [[horizontal gene transfer]] could occur between the older, formerly frozen bacteria, and modern ones, and one outcome could be the introduction of novel [[antibiotic resistance]] genes into the [[genome]] of current pathogens, exacerbating what is already expected to become a difficult issue in the future.<ref name="Sajjad2020">{{Cite journal|last1=Sajjad|first1=Wasim |last2=Rafiq |first2=Muhammad |last3=Din|first3=Ghufranud|last4=Hasan|first4=Fariha |last5=Iqbal|first5=Awais |last6=Zada|first6=Sahib|last7=Ali|first7=Barkat|last8=Hayat|first8=Muhammad |last9=Irfan|first9=Muhammad|last10=Kang|first10=Shichang |date=15 September 2020|title=Resurrection of inactive microbes and resistome present in the natural frozen world: Reality or myth? |journal=Science of the Total Environment|volume=735 |page=139275 |doi=10.1016/j.scitotenv.2020.139275|pmid=32480145 |bibcode=2020ScTEn.73539275S |doi-access=free}}</ref><ref name="Miner2021" />

At the same time, notable pathogens like [[influenza]] and [[smallpox]] appear unable to survive being thawed,<ref name="Doucleff2020">{{Cite web|url=https://www.npr.org/sections/goatsandsoda/2020/05/19/857992695/are-there-zombie-viruses-like-the-1918-flu-thawing-in-the-permafrost|title=Are There Zombie Viruses — Like The 1918 Flu — Thawing In The Permafrost? |first1=Michaeleen |last1=Doucleff  |website=NPR.org |access-date=2023-04-23}}</ref> and other scientists argue that the risk of ancient microorganisms being both able to survive the thaw and to threaten humans is not scientifically plausible.<ref name="Yong2014">{{Cite news|url=https://www.nature.com/articles/nature.2014.14801/ |title=Giant virus resurrected from 30,000-year-old ice |first1=Ed |last1=Yong |date=3 March 2014 |website=[[Nature (magazine)|Nature]] |access-date=2023-04-24}}</ref> Likewise, some research suggests that antimicrobial resistance capabilities of ancient bacteria would be comparable to, or even inferior to modern ones.<ref name="Perron2015">{{Cite journal|last1=Perron|first1=Gabriel G.|last2=Whyte |first2=Lyle|last3=Turnbaugh|first3=Peter J.|last4=Goordial|first4=Jacqueline|last5=Hanage|first5=William P.|last6=Dantas|first6=Gautam |last7=Desai|first7=Michael M. Desai |date=25 March 2015|title=Functional Characterization of Bacteria Isolated from Ancient Arctic Soil Exposes Diverse Resistance Mechanisms to Modern Antibiotics |journal=PLOS ONE|volume=10 |issue=3 |pages=e0069533 |doi=10.1371/journal.pone.0069533 |pmid=25807523 |pmc=4373940 |bibcode=2015PLoSO..1069533P |doi-access=free}}</ref><ref name="Wu2022">{{Cite journal|last1=Wu|first1=Rachel|last2=Trubl|first2=Gareth|last3=Tas|first3=Neslihan |last4=Jansson|first4=Janet K.|date=15 April 2022|title=Permafrost as a potential pathogen reservoir|journal=One Earth |volume=5|issue=4|pages=351–360 |doi=10.1016/j.oneear.2022.03.010 |bibcode=2022OEart...5..351W |s2cid=248208195 |url=https://escholarship.org/uc/item/50s30845 }}</ref>

==== Plants ====
In 2012, Russian researchers proved that permafrost could serve as a natural repository for ancient life forms by reviving a sample of ''[[Silene stenophylla]]'' from 30,000-year-old tissue found in an [[Last Glacial Period|Ice Age]] squirrel burrow in the [[Siberian]] permafrost. This is the oldest plant tissue ever revived. The resultant plant was fertile, producing white flowers and viable seeds. The study demonstrated that living tissue can survive ice preservation for tens of thousands of years.<ref>{{Citation|last=Isachenkov|first=Vladimir|title=Russians revive Ice Age flower from frozen burrow|date=February 20, 2012|url=http://phys.org/news/2012-02-russians-revive-ice-age-frozen.html|newspaper=Phys.Org|archive-url=https://web.archive.org/web/20160424214832/http://phys.org/news/2012-02-russians-revive-ice-age-frozen.html|access-date=2016-04-26|archive-date=2016-04-24|url-status=live}}</ref>